This invention relates generally to devices for displaying addresses on a record medium, which is suitable for use in an apparatus for reproducing a signal from a record disc, such as a digital audio disc player, and more particularly, is directed to an address displaying device which can display visually the contents of address information obtained from a record medium in an improved manner.
A digital audio disc, which is a rotatable disc having a spiral record track in which a digital audio signal is recorded as program information together with address information, has been proposed to be loaded on a disc player to obtain a reproduced audio signal. Digital signals which are to be recorded on the digital audio disc are formed, for example, to have a data format containing successive frame segments. The duration of each frame segment is 136.1 .mu.sec and therefore the repetition frequency of one frame segment is 7.35 kHz, for example, as shown in FIG. 1. In FIG. 1, the frame segments are arranged vertically for convenience' sake. Each frame segment comprises a portion 1 containing a frame synchronous information A, a subcoding portion 2 and a data portion 3. The subcoding portion 2 contains address information forming a unit whithin each block segment which comprises 98 frame segments. The duration of each block segment is 13.3 msec and threrfore the repetition frequency of one block segment is 75 Hz. Each subcoding portion 2 is divided into eight channels including channels P to W, and the subcoding portions 2 in the first and second frame segments at the beginning of each block segment are provided through the channels P to W therein with block synchronous information B and C, respectively, while each of the subcoding portions 2 in the remaining 96 frame segments forming the block segment in cooperation with the first and second frame segments is provided at the channel Q therein with address information accompanying with program information in the data portion 3.
FIG. 2 shows one example of a data format of the channel Q. The channel Q in this example includes the block synchronous information B and C, a portion 4 representing a music number m as an example of a number for each program information section, a portion 5 representing a movement number n as an example of a number for each part of one program information section, and portions 6, 7 and 8 containing time address information representing running time within each part of one program information section, which is expressed in minutes, seconds and deciseconds. These synchronous information and address information in the channel Q are inserted dispersedly into the frame segments forming one block segment in such a manner that each one bit thereof is contained in each of the frame segments, as shown in FIG. 1. Each of the portion 4 representing the music number m, the portion 5 representing the movement number n and the portions 6 and 7 containing the time address information representing the time expressed in minutes and the time address information representing the time expressed in seconds, respectively, is formed with eight bits, and the portion 8 containing the time address information representing the time expressed in deciseconds is formed with four bits.
As mentioned above, the address information forms one unit thereof within each block segment. Therefore, a unit of address information is obtained at every block segment, that is, at every 1/75=13.3 msec, in reproduction of signals from the digital audio disc. In such a case, the minimum piece of the address information which is the time address information representing the time expressed in deciseconds corresponds to 1/10 sec, and since this minimum piece of the address information is 7.5 times as long as the duration of the block segment, the same unit of address information is obtained from each successive seven to eight block segments.
Since the address information is recorded on the digital audio disc to accompany with the program information sections, it is possible to detect the location on the digital audio disc from which the program information and address information are read out by a pick-up device by deciphering the address information obtained from the pick-up device when an audio signal is reproduced from the digital audio disc by a disc player. Accordingly, in reproduction of the audio signal from the digital audio disc, if the contents of the address information obtained from the pick-up device is visually displayed by a display device, it is possible to easily know the location on the digital audio disc from which the program information is read out by the pick-up device to reproduce the audio signal.
FIG. 3 shows a part of a recording format of the program information recorded on the digital audio disc in which a boundary between two successive program information sections is included. In FIG. 3, a first program information recorded portion 9 where, for example, a first music information is recorded as one program information section and a second program information recorded portion 10 where, for example, a second music information is recorded as the next program information section are provided. A plurality of program information recorded portions in each of which a music information is recorded as a program information section, such as the first and second program information recorded portions 9 and 10, are formed successively in the spiral record track on the digital audio disc, and each of the program information recorded portions comprises a pause division 11 where no program information is actually recorded and first, second, --movement divisions 12a, 12b, --in each of which each movement information contained in the recorded music information is actually recorded together with the address information.
To cite the second program information recorded portion 10 by way of example for explaining the divisions in each program information recorded portion, in the second program information recorded portion 10, the pause division 11 where no program information is recorded is provided at the beginning end and the first movement division 12a, the second movement division 12b, --in which the first movement information, the second movement information, --in the second music information are recorded, respectively, are provided in succession to follow the pause division 11 as far as the terminating end to which the next program information recorded portion follows. Each program information section such as the music is thus recorded with a predetermined recording format.
On the other hand, the address information accompanying with the program information is recorded through the whole divisions in each program information recorded portion. For example, positional address information representing the aforementioned music number m and movement number n and the time address information representing the aforementioned running time expressed in minutes, seconds and deciseconds, which form each unit of the address information, are continuously recorded with predetermined data as information indicating the position of each music as a program information section. That is, the address information is recorded also in the pause division 11 in each program information recorded portion.
Next, the time address information representing the time expressed in seconds in the pause division 11 and the first movement division 12a following to the pause division 11 will be explained with reference to FIG. 4. The time address information representing the time expressed in seconds recorded in the pause division 11 contains data reducing toward the first movement division 12a. That is, assuming that the reproducing time for the pause division 11 is approximately three seconds in reproducing the audio signal from the digital audio disc, the data of the time address information representing the time expressed in seconds recorded in the pause division 11 are arranged to vary in turn to be, for example, 0 2 .fwdarw. 0 1 .fwdarw. 0 0 along the direction for reading the record track, as shown in FIG. 4. On the other hand, the data of the time address information representing the time expressed in seconds recorded in the first movement division 12a are arranged to take 0 0 at the beginning portion of the first movement division 12a corresponding to the first one second and then increase every one second so as to vary to be 0 0 .fwdarw. 0 1 .fwdarw. 0 2 --along the direction for reading the record track, as shown also in FIG. 4. In this case, the data of the time address information representing the time expressed in seconds are arranged to take 0 0 at both of the end portion of the pause division 11 corresponding to the last one second and the beginning portion of the first movement division 12a corresponding to the first one second. This results from that the time address information representing the time expressed in deciseconds is recorded together with the time address information representing the time expressed in seconds as shown in FIG. 4 and the data of the time address information representing the time expressed in seconds are arranged to take 0 0 at the portion of each division corresponding to the time less than one second. Incidentally, the positional address information representing the music number m and the movement number n with the respective data is recorded in both of the pause division 11 and the first movement division 12a.
FIG. 5 shows the variations at every one second of the data of the time address information which is recorded in the pause division 11 and the first movement division 12a in the second program information recorded portion 10 in such a manner as mentioned above. In FIG. 5, the data of the time address information representing the time expressed in seconds, which are surrounded by a dot-dash line, vary to be 0 2 .fwdarw. 0 1 .fwdarw. 0 0 .fwdarw. 0 0 .fwdarw. 0 1 .fwdarw. 0 2. That is, the data of the time address information representing the time expressed in seconds take 0 0 twice repeatedly at the boundary area between the pause division 11 and the first movement division 12a. Accordingly, when the address information recorded at such boundary area is reproduced by the disc player and the contents of the reproduced address information are visually displayed by the display device provided in the disc player, the time display resulted from the data of the time address information representing the time expressed in seconds shown 0 0 continuously during two seconds. This results in the disadvantage that the time display is performed quite unnaturally. Further, when the time display shows 0 1 or 0 2 in accordance with the data of the time address information representing the time expressed in seconds, a person who watches the time display at that time can not discriminate whether such data of the time address information representing the time expressed in seconds as causing the time display to show 0 1 or 0 2 are obtained from the pause division 11 or the first movement civision 12a, and this is very inconvenient for the person who watches the time display.
As apparent from FIG. 5, the data of the positional address information representing the movement number n, which are surrounded by a double dot-dash line in FIG. 5, are arranged to take 0 0 in the pause division 11.